Drawing board



April 18, 1933. A, KEUFFEL 1,904,899

DRAWING BOARD Filed Nov. 28', 1951 5 FIGJ. 2,1 ze

L H o 8 Z 12 3 3713 16 gig/ 6 4 4 25 r 25 13 ,agmwzgu Illi- ADOLF W. lfEl/FFEL BY HIS ATTORNEYS Patented Apr. 18, 1933 ADOLF w.. KEUrFEn-oEnoNrciArIanEuf inssrsnonl e01mwasrafassmcb;

or nonoxnn, NEW mn'snr',n enamele ornnwygrnasny Application filed Kovemlier 283-i9lt1'b ShrfalfNol i i This invention relatesv to struction and more particularly" to-theccnstruction of drawing boards,- drafting tables and the like in which one .or more edges or cleats are adapted to guide a IT-square: or other drawing instrument. V These cleats also serve as means for keepinggthe board flat,

The edge of such a board must bedurable, so thatit will not: be worn by the friction with 10 the co -operating edge of the T-square andit must be hard so that itsjedge will alway s be straight and will not-warpout of shape. or

become mutilated by objects knocking against it; On the other hand, the surface offthe drawing board must be of Va soft material so as to receive thumb tacks: holdingthedrawing material in place and also so as to-form a proper supporting surface for the paper over.

which the drawing pentravels, It has heretofore been proposed to form the top of a drawingboard of white pine or similar relatively soft wood, them-grain of which, of course, general-1y runs in the long direction of the board... This top is-bordered at one or both ends, transverseto the grain of the top, with an end; cleat of maple or other relatively harder wood. Suchwcleats have been fastened tothetopwith screws. The top expands and contracts-withrespect to the cleat in a directionnsualjly transversely to the direction of expansionand contraction of the cleat, and to a different degree The screws are passed throughelongated; holes the-cleat to permit such rel-ative mevement. In some prior constructions, :the screws have been passed through the end cleat into the end of the topiin the direction of the end grain. Such construction wasnotdurahis because the soft end grain of. the Wood into which the screws were: .threaded,did not aiford a secure base for the screw. threads and readily became mutilated" so ;,that.1;the

' screws sometimes pulled out of'the-to'p or be:- 4 came loosened therein. The present invention has-for object a connection between the end chat and the. top

of a drawing board which: shall. avoid mutilation of the softer material.

The invention alsoseeksanonstrnctiorrin which the means securingthe parts together cannot readilywork loose therefrom. 'In accordance with the invention; inaits broadest aspect; the securing means fastening the; parts together are seated in the ha rder material; of the'end cleat and vprovision-is made in the softer material for relative movement-between the securing means'and the softer material. More particularly,; =the softer material is formed with a passage for so each securing means, which passage is elon-f gated inthedirection of the expansion of the softer material, -so that no strainis placed thereonlin its expansion and contraction. I

The invention also seeks to prevent wear ofthesofter material where it comes in contact with; the securing mean's. To this end, thelpass'afge in the softer material is: prefer-- ably separatedfrom the harder'material of the securing means by wear resistant material,as by lining the passage, at -{least in part, with a metal plate or bushing.

' Itisalsoanobject ofthe inventionto predamage to the threads of the screw or other-securing means. Accordingly, threaded securing meansmaybe surrounded ;by a bushing which seats within the elongated opening, or*bushingtherein, in the softer material. and "prevent'scontact therewith. The invention also seeks a. construction which overcomes the strainon the softermateria-l in aseparation of the parts-and to this end" thesofter materialis clamped between "portionsofthe harder material and the securingmea'nsis relied upon to clamp-the partstogetheri i Another (object of the inventionuis to prevent separation-of the parts shearing action at the-joint therebetween. According y, a portion of; one of the parts underlies aportion of the other part.,- 1

. .-,The invention also has to do with a con structionwhich is practical from the standpoint ofrease and cheapnessof manufacture and" convenience and durability in use. In carrying theji'nvention into effect, in its preferred embodiment, the top I is formed 7 along. one edge withatongue which is-recoived in a groove in'an'end cleat and screws passing freely through holes-in onewall of I00 board, taken at one'of the securing means.

screws, and to prevent wear of the material 7 of the tongue, the holes may be lined,firespectively, with elongated bushings. Similarly, to prevent wear of the screw threads,

the screws may be surrounded with bushings which are within the first'named, bushings and enter the holes in the cleat. 4 These and other objects of the invention and the means for their attainment willbe more apparent'from the following detailed description, taken in connection with the accompanying drawing illustrating various embodiments by which the invention may be realized, and in which Figure 1 is a fragmentary view, partly-in vertical section and partly in perspective, through the end cleat and top of a drawing Figure 2 is a horizontal sectional View taken in the planes indicated by the broken line 22 in Figure 1 and looking in the di rection of the arrows. I

' Figure 3 is a view similar to Figure 1, but showing a modification of theinvention in which the securing means is provided with a plane surface where it comes-in contact with the softer material ofthe top to avoid mutilation. v

Referring to the drawing, Figure 1 shows a fragmentary portion of a drawing board at one of its shorter edges. The top is indicated at 4. By the term top it is intended to denote the board or surface to which the drawing paper or the like is secured, as by thumb tacks. This top 4 is usually formed of some soft material, such as white pine, which will readily receive thumb tacks holding the drawing paper to its upper surface 5. The lower surface of the top is indicated at 6.

This top. 4 is formed with a rebate along at least one edge, usually one of the shorter edges, as the board is generally oblong. This rebate is defined by a vertical edge 8 setinwardly from the outer marginal surface of the top and extends downwardly from the upper surface 5'for a material distance, for instance, approximately half the thickness of the top 4, and a surface 10 which lies in a plane parallel to and intermediate the top and bottom surfaces 5 and 6. The extreme outer edge portion of the top below the rebate isindicated by the numeral 12 and the material below the rebated part forms a tongue 13. Generally the grain of thetop runs parallel to the longer dimension of the board, that is, the end surface 12 lies inv a plane transverse to the grain.

The end edge of a drawing board must be hard and durable so that it will retain its straight shape and form a guide, say, for a T-square. Accordingly, an end cleat of relatively harder material, such as hard wood, for instance, maple, is secured to the edge of the top 4. 1

. The end cleat is formed, preferably, with a horizontally extending preferably rectangular groove defined by the upper surface 14 and the lower surface 16 and a bot tom, 18. The vertical dimension of the groove between the surfaces 14, 16 is substantially-equal'to the vertical dimension of the tongue 13 between the surface 10 and the bottom surf-ace 6 of the top but the depth of thegroove' from the surface 26 to the bottom 18 is preferably somewhat greater than the corresponding dimension of the tongue 13.

The groove may be considered to define ledges'forming' the sides of the groove, the upper ledge being indicated at 21 and the lower ledge at 25. The upper surface of the upper ledge 21-is indicated at 20 and lies substantially in the plane of the top surface 5, the end surface of the cleat is indicated at 22 and the bottom surface of the lower ledge 25 is indicated at 24. On the side of the cleat opposite the end surface 22, the inner surface of the upper ledge is indicated at 26. When the two parts, cleat and top, are assembled, thesurface 26 of the upper ledge 21'abuts the surface 8 of the top.- The lower ledge 25 extends inwardly beneath the top 4 further than the upper ledge 21 so as to underlie the top 4. It thus extends beyond the plane including the surfaces 8 and 26, which is the plane in which thetongue 13 might be broken off from'the top 4 by shearing stresses and thus the lower ledge 25 resists such shearing stresses. 7

The bottom ledge 25 of the end cleat is formed at predetermined points with holes 30. The tongue 13 is formed with. holes 32, in register with these holes 30. Securing means such as screws '37 pass through these holes 30 and 32 and are seated in the upper ledge 21; As has been pointed out, the top '4 is subject to'expansion and contraction in a direction transverse to the grain of the top and parallel to the longitudinal axis of the cleat; The holes 32 in the tongue 13 are elongated in the direction transverse to the grain so that relative movement of the top 4 is permitted in that direction, with respect to the cleat.

'Toprevent the securing means from damaging the relatively softer material of the top 4, the holes 32 on their diameter on the longer dimension of the board are sufficiently greater than the diameter of the holes 30 so as to. receive a bushing 34 of wear resistant material. This bushing 34 is preferably elongated in cross section to permit such relledge 21'.

apozgsoe ative fmovem-ent and is" conveniently made of is guided or held against displaoement'into' contact with the threadsnot only by its fit in hole 30"but also by bushing 34, if desired.

Preferably,.the sleeve 36 is of a length such that when abutting the surface 14 of the up per ledge 21, it does not extend tothe'bottom surface 240i the lower ledge =so that thehole may receive in part,.at least, the

head of the a wood screw 37 and the screw; be

thus substantially countersunk within the marginal surface 24.

When the partsvare secured togethenjas illustrated in Figure 1, wood screws 37 are passed through the holes 30 within the bushing 36 and are seated or threaded into the bears against the bottom surface 24 of the end cleat, the two ledges 25 and2l are drawn together, clamping between themithe tongue 13, thus securely holding the parts together while permitting expansion of the top A, {in

the directionof its shorter dimension by'reafson of the elongated slots In Figure 3 there is illustrated a 'fication of the invention in which the elongated slot 32 receives a plain or unthreaded portion40 of a screw 42. Thus there are-no threads-to injure the softer wood; By reason of the taper of the threadediportion of the screw, whenithe parts are in clamping engagement a force iseX-erted as indicated by the arrow 44bythe end 26 pressing against the face 8. The reaction of the shank otthe screw to this force 44 is indicated by the arrow 46andcauses the shank 4:2 to bear only against the left hand sideot elongated slot 32, as viewed in Figure/3.- :Hences it;i s on-lynecessary, if desired, to provide-that side of the elongated slot with wear resistant material, as indicated :at '50. This "material 50 maa be a Plate of metal, k;

It will thus beseen that means are provided, in a drawingboard or thelike, which prevents separation of the hard and soft materials at the joint While at the sa ni ewtiine the securing means is seated, solely the hard material and wearot the soft material is in i great measure avoided, particularly 7 where a wear resistant nieans; is interposed between the securing meansand the softer material; v r A Various modifications wi-l-L occur to-those walls. of c the groove When the head of the screw thus skilled in the art in the composition and con figuration of the loo-acting and component elements of this. invention, and nolimitation.

intended by the phraseology-of the foregoing specification or"illustrations the ac companying except as indicated the appended'claimsfl g a 1. In a device of the character. described,

in combination, a top having a tongue :along ,at l eastone edge-thereoflat least one end cleats formed with "a groove to i receive: a

tongue, and means seated in the respective sidesjof the groove and d-rawin-guthe sides of thelgroove together to clamp the tongue therebetween. j a 7 :2. In a device of the character described,

combination, a top having a tongue along at" least one edge-Ytherebfgnt least one end cleat. formedwith ang'roo-ve to receive a tonguacandmeanspzassing freely through the wall on one side of the groove and seated in the other wall :of thergro'ove to draw the tongue therehetween. a

13. In a deviee of the" character described,

incombinatioma top having atonguewalong at least one edge thereof, at least one end cleat formed: with a groove to receive a tongue,

and-l'means passing freely through the wall ionlone side of thegroove and passing freely wall of the grooveto draw the walls of the groovetogether to clamp the tongue therebetween. -E: 13:45.; In aidevie.

together to clampthe 4 throughsthetong ue and seated in theother' azoo "of the character described, V n combination 'a top =formed with a tongue along at least one edge, at least one endcleat formed with a groove defining spaced ledges,

said groove, receiving the tongue, at least one hole in one of the-ledges, at least one holeformed in the 't'ongsiie in register with said 1 hole, and 5 "securing means Ipass'ing through theholes and-secured in the other m lledge, said hole inthe tongue being greater in at least one dimension than the corresponding dimension ott the securing means.

5.. In andevicenot the characterdescribed,

in combination,.as top formed with a' tongue along at least one edge, at least one end cleat formed with a groove defining an upper and alower ledgasaid groove receiving a tongue, at least :one-iho-le' in the lower ledge, at least 0J3l-1hbl6 formed in'the tongue in register with'said hole, and securing means passing through the holes and securedin the'upper ledge, said hole in'the tongue being greater inflate lea-stone dimension than the corresponding' dimension of the securing 'm'eans.

. 6. In adevice ofthe character described,

incomhiuation, a topfolrmed witha tongue alongat leastjone edge, atleast one endcleat formed with a'groove defining spaced ledges, said groove 1 receiirin the tongue, at least :OIlQhlOlfi :in'onewof t ewledgesyattleast one hole formed in the tongue in register'with said hole, and securing means passing through the holes and secured in the other ledge, one of said holes being greater in at least one dimension than the corresponding dimension ofsaid securing means.

7, In a device of the character described, in combination, a top formed with a tongue along at least one end, at least one end cleat formed with a groove to receive a tongue, said groove defining upperand lower ledges, one of said ledges being formed with a plurality of holes, said tongue being formed with elongated holes in register, respectively, with the holes in the ledge, the major axis of said holes being substantially parallel to the longitudinal axis of the cleat, and threaded securing. means passing through the holesand seated in the other ledge.

8; In a device of the character described, in combination, a top formed with a tongue along at least one end, at least 'oneend cleat formed with a groove-to receive a tongue, said groove defining upper and lower ledges, one of said ledge-s being formed with a plurality of holes, said tongue being formed with elongated holes in register, respectively, with the holes in the ledge, the major axis of said holes being substantially parallel to the longitudinal axis of the cleat, a bushing passing through the holes, and threaded securing means passing-through the holes and seated in the other ledge.

9. In a' device of the character in combination, a top formed with a tongue along atleast'one end, at least one end cleat formed with a groove to receive a tongue, said groove defining upper and lower ledges, one of said ledges being formed with a plurality of holes, said tongue being formed with elongated holes in register, respectively, with the holes in the ledge, the major axis of said holes being substantially parallel to the longitudinal axis of the cleat, a bushing within the hole in the tongue, and threaded securing means passing through the holes and seatedin the other ledge.

. 10. In a device of the character described, in combination, atop formed with a tongue along at least one end, at least one end cleat formed with a groove to receive a tongue, said groove defining upper and lower ledges, one of said ledges being formed with a plurality of holes, said tongue being formed with elongated holes in register, respectively, with the holes in the ledge, the major axis of said holes being substantially parallel to the longitudinal axis'of the cleat, a bushing within the hole in the tongue, a bushing within the hole in the cleat and entering the bushing in the tongue, and threaded securing means passing through the holes and seated in the other ledge. v I

11. In a device of the character described, in combination, a top formed with a tongue described,

along at least one end, at least one end-cleat formed with a groove to receive a tongue, said groove defining upper and lower-ledges, one of said ledges being formed with aplurality of holes, said tongue being formed with elongated holes in register, respectively, with the holes in the ledge, the major axis of said holes being substantially parallel to the longitudinal axis of the cleat, a bushing within the hole in the tongue, a bushing within the hole in the cleat and entering the bushing in the tongue, and a screw passing through the last named bushing and threaded into the other ledge.

12. In a device of the character described, in combination, a top formed with a tongue along at least one edge, at least one end cleat formed with agroove defining spaced ledges, said groove receiving the tongue, at least one hole in one of the ledges, at least one hole formed in the tongue in register with said hole, securing means passing through the cleat of relatively harder material formed with a'groove to receive a'tongue, said groove being of greaterdepth than the widthof the tongue, defining an upper ledge to be received in therebate and a lower ledge ofigreater width to underlie the top inwardly of the tongue, a plurality of holesformed in the lower ledge, a plurality of elongated holes formed in the tongue in. register with the holes in the ledge, respectively, the major axis of said last named holes being substantially parallelto the longitudinal axis of-the cleat, wear resistant material lining the hole in the tongue, a bushing of wear resistant material within the hole in the tongue and extending at least part way into the hole in the cleat, and a wood screw passing through thelast named bushing and threaded into the upper ledge to clamp the tongue between the ledges.

14. In a device of the character described, in combination, a top of relatively soft wood formed along at least one edge, across the grain, with a rebate defining atongue rectangular in cross-section, at least one end cleat of relatively harder wood formed with a groove, rectangular in cross-section, to receive a tongue, saidigroove being greater in depth than thecorresponding dimension of the tongue and defining an upper ledge to be received in the rebate and a lower ledge, said lower ledge being wider than the upper ledge to underlie the top inwardly of mg at least part way into the holes in the 1 lower ledge and screws passing through the last named bushings and threaded into the upper ledge to clamp the tongue between the ledges.

15. In a device of the character described, in combination, a top formed with atongue along at least one edge, at least one cleat formed with a groove to receive a tongue,

said groove defining spaced ledges, one of said ledges being wider than the other .to

overlie the top inwardly of the groove, and

means drawing the ledges together to clamp the tongue therebetween.

16. In a device of the character'described,

in combination, a top formed with a tongue I along at least one edge, at least one cleat formed with a groove to receive a tongue said groove being greater in depth than the corresponding dimension of the tongue, said groove defining spaced ledges, one of said ledges being wider than the other to overlie the top inwardly of the groove, and means drawing the ledges together to clamp the tongue therebetween.

In testimony whereof I alfix my signature.

ADOLF W. KEUFFEL. 

